Turns out a single spal 12" mounted directly to OEM radiator isn't enough to keep temps in check once everything heat soaks and dual driving.

Temps would actually drop back to 90c while moving on course but as soon as we got back to grid, even with me spraying the radiator and oil cooler, would creep up to over 100c idling. If I shut the car off, we were having hot start issues because something isnt tuned right for 110c restart. 110c because the coolant just heat soaked the engine block sitting there. Issues I of course have never had before with the stock fan and was told this would likely happen :lol:.

Was totally fine solo driving sunday though. Minus the check valve thing. Time to order the CSF full size slim to go on before nats.

no shroud? I dont idle my car long, but i also have the condenser fan

crap i didnt know that. I am having trust issues with these flimsy heim joints (+ the length of the tapered part). i have enough issues to monitor on this car ugh.

Bartley said there might be SSB toe arms at some point?

Absolutely nothing wrong with 100c water temp. 110c is pushing it, but if you're only seeing that with engine off heat soak, its also not too worrisome.

There was a compounding bag of issues that all made things a struggle at that moment.

• The motec is set to limit RPM above 100c. I'll push that to taper from 100-110 so it limits 8200 down to maybe 5000.
• The check valve basically made a huge boost leak but "luckily" I lost the dipstick on the catch can so it was venting most of the boost/vacuum.
• The bosch throttle body for some reason cant get to really low positions at idle and accumulates an error eventually causing motec to just shut down the TB. Its asking for 0.6% and only able to get down to 1.3% when running. Im not sure if the vacuum is pulling it open or something. I also wonder if my PCV system is too free flowing and not leaving room for the TB to control idle at a reasonable angle.
  • This was a pain because if you idled after everything was fully hot, it would all the sudden rev to 2000-2200rpms which was not really hurting anything but very annoying and another distraction.

So far the Motec and DBW makes life 98% better. But theres still a few bugs in my system to sort out.

That sounds like your PCV flows too much. Typically a DBW throttle will idle at anywhere from 5-20%

I had myles check his car to see what it was idling at and IIRC it was 5 or 8%, so it was a bit fishy for sure. I'll plug the PCV line and see what it increases to.

Boost leak check did find a couple leaks but those are all fixed now. Will do one again for good measure before nats though.

What is your idle speed set to? I agree that under 2% throttle position is abnormally low, if your old PCV valve was stuck open then that could certainly contribute to that.

As for coolant temps 110C is definitely pretty hot for a hot idle. Might be worth experimenting with making a simple shroud with speed flaps, allows the fan to pull harder at idle but opens up when the car is at speed.


On another topic, we were talking about aftermarket heads here the other week, looks like PRP is doing cast Subaru heads now on top of their RB stuff. I know Herman has teased 4G stuff in the past so I don't think it's out of the question that we could see an improved cast head from PRP:

I dont have the stock PCV system, is set up as the drawing below. The check valve at the intake manifold is what failed on me, so there was basically just a straight line to the Tee with a 3/8 line. Thats a lot of line to suck/blow and when the valve failed it was pushing lots of air right back to the valve cover and intake pipe.

Hopefully the new check valve has enough restriction to give idle control back to the TB.


https://cimg4.ibsrv.net/gimg/www.evo...e07c072969.jpg

I have a single 10" spal fan mounted on the back side of the radiator on the gearbox side and i can come off the track hot and idle away for 20min and it will bring temps down to around 85. Also if i run the car up from cold at idle i could let it idle all day and it doesnt creep above 82. Seems to be another issue your having there causing temp issues. I found i used to struggle to keep temps down before i put a decent koyo radiator in. Also when i had fans on the front side of the radiator they were definitely less efficient despite having 2x 12" fans than the single 10" i have now. Not shrouded either by the way.

Ill check what my idle % is at with my Bosch DBW but i dont have any issues like your having with idle position. Granted i dont run a PCV system. i think from memory it sits around 5-6% at idle.

some autox folks with smaller venues dont get enough cool down before getting back to grid
what type was that check valve that failed? I wanted to be able to use the PCV to raise idle manually, replacing the BISS(strutbar gets too hot). I bought a PCV for subies which flows more, and I'm still cooking up the adjustable valve

are you guys running coolant or water?

I would recommend a proper pcv designed to avoid the vacuum leak symptoms you may get from a check valve. Radium makes a really good one Radium PCV

TBH, I didn't even know the PVC valve was anything more than a 1way check valve. I always assumed the OEM valve was just a ball and spring. But that would be perfect since I have the Radium catch can right there.